The approaching heating season will bring with it increased responses
to heating emergencies. These emergencies are often the result of a
malfunctioning oil burner. Conditions you usually find on arrival-smoke
pouring from a basement or cellar-indicate a malfunctioning heating
system.

TYPES OF EMERGENCIES

Puff back/delayed ignition. There are several types of oil burner
emergencies to which you may respond. One common type is the puff back or
delayed ignition. This occurs when atomized oil is delivered to the
combustion chamber but is not immediately ignited. When it finally
ignites, an explosion in the firebox takes place ranging from a small thud
accompanied by a puff of smoke to a blast that blows the firebox door open
and sends a jet of flame across the room. The blast can also knock the
flue pipe down. Once the burner door is opened or the flue pipe is down,
the burner room and the entire basement rapidly fill up with smoke. If the
door is not blown open and the ductwork is not blown down, most of the
smoke is channeled up and out the chimney.

A properly functioning oil burner generates little smoke. You will see
wispy white smoke exiting the chimney. The color of the smoke resulting
from a puff back, however, ranges from dark gray to black, depending on
how much soot has been shaken loose from the burner and is entrained in
the smoke. Seeing this black smoke exiting the chimney, a neighbor often
calls the fire department and reports black smoke coming from the roof.

When you arrive on the scene of the oil burner emergency, you see smoke
issuing from either the chimney, if the flue is intact, or the cellar or
basement openings. The smoke is relatively cool and deceptively easy to
tolerate. However, it does contain carcinogens that require mask use.
Basically, all you need to do is shut down the burner, shut the fuel
supply, and ventilate the building.

A puff back is usually an emergency-not a fire. It is possible though
that, when the puff back occurs, a jet of flame will momentarily leap out
from the open door or peephole or that burning oil droplets will be
scattered about the basement. The jet of flame or the flaming drops of oil
can ignite nearby combustibles. If a great amount of oil is scattered in
this way, you may encounter a burning pool of oil on the ground in front
of the burner. You may now be faced with a structure fire and, depending
on the extent of the fire spread, call for a handline. You can handle
small spot fires with a water extinguisher and burning oil with a foam or
dry chemical extinguisher. A foam extinguisher should be your extinguisher
of choice at an oil burner emergency. It works well on fires in Class A
combustibles as well as oil fires. As a precaution, stretch a handline if
the fire is out of the firebox.

After fire. Another condition you may encounter is after fire. This
occurs when, because of a malfunction, excess oil pools in the firebox and
continues to burn after the burner cycles off. When the burner shuts down,
the fan shuts down and, as a result, the required quantity of oxygen is
not supplied to the flame. The flame becomes oxygen-starved and can
produce large quantities of thick, black smoke. The after fire will
continue to burn until you extinguish it or until the excess oil is
consumed. This is also an emergency-not a structure fire. The fuel burning
in the firebox does not necessarily pose a danger, since the firebox is
designed to withstand the temperatures associated with an oil fire. It
will eventually burn itself out if left alone and if there is not an
ongoing fuel leak feeding the fire in the combustion chamber. It is
possible, however, for the flame to rise into the ductwork exiting to the
chimney. Always check for fire extension around the ducts, especially when
they are near joists, studs, or any other flammable material.

When you encounter after fire or puff back, shut down the electric and
fuel supply to the burner, check for extension, and ventilate the area and
the building if necessary. If the burning oil is escaping the firebox or
threatening to extend to the building's contents or structure, then you
must extinguish the fire. Do so with the judicious application of water or
dry chemical or foam. If you use water, be wary of a steam explosion that
may splatter hot or burning oil. Unless you cool down the hot firebox, the
fire may reignite and need to be extinguished again.

Pulsation. A less common emergency, pulsation occurs when the flame
repeatedly jumps away from and then back to the nozzle in the combustion
chamber, creating a rhythmic pulsation that increases in intensity until
it feels like a freight train is speeding past the house. The pulsation
can force the combustion chamber open. To prevent the door from opening, a
well-meaning homeowner may brace a piece of wood or metal against the
door, creating a very dangerous condition. Because the door can't blow
open to relieve the built-up pressure, the burner becomes a time bomb.
Severe pulsation coupled with a braced combustion chamber door could cause
the burner to rupture explosively. While simply opening the door should
stop the pulsation, your initial action should be to kill the power and
shut down the fuel supply before approaching the burner.

Another condition you may respond to is the blocked or dislodged flue
pipe. This can occur because of a number of reasons. A bird's nest or
other debris in the chimney can block the flue, or a pipe dislodged by a
worker or a puff back can result in the flue pipe's becoming dislodged
from the chimney. The result will be a smoke-filled basement or house.
Your action would be to shut the electric and fuel supplies and ventilate
the area. If smoke has been diverted from the flue and into the structure,
also check the building for buildup of deadly carbon monoxide (CO).
Because CO, a product of burning fossil fuel, is life-threatening, check
all occupants and all parts of the building for CO poisoning. If you find
potentially dangerous levels of CO, evacuate the building and ventilate.
Only when CO levels are determined safe can occupants return to the
building. You may need ventilation fans to clear CO out of cellars and
other windowless areas. Fans can also help speed up the ventilation
process in other areas of the building.

A myriad of faults can cause an oil burner emergency or fire. Because
of the many oil burners in use throughout the country, oil burner
emergencies are fairly common.

White ghost. One thankfully rare oil burner-related problem is the
white ghost. It is often preceded by hard starting and then by puff back.
Eventually, as the condition of the burner deteriorates, the white ghost
appears.

The temperature of an oil burner's combustion chamber can be as high as
2,6007F. If a burner has been operating for some time and ignition fails,
and if fuel is still delivered to the hot combustion chamber, it may be
vaporized by the existing high heat. The vaporized fuel oil becomes
entrained in the smoke, turning it a pearly white and giving it an oily
smell. This vaporized fuel fills the combustion chamber, the flue, and the
chimney. If the flue is intact and if the combustion chamber door is
closed, this flammable vapor vents harmlessly out of the chimney. If the
flue piping has been blown down by a puff back or is disconnected, or if
the draft in the flue is reversed, the vapor can fill the burner room or
the entire basement. Once the fuel oil has been vaporized, all that is
needed to trigger a devastating explosion is for the vapor to encounter an
ignition source. The ignition source can be provided by the burner cycling
into an ignition sequence or the presence of an open flame, sparks, or
embers in the basement. This explosion could be accompanied by a large
flame front that fills the basement and leaps out of the basement windows
and other openings. The pressure from the explosion could cause structural
damage to the building. Being in the basement during a white ghost is like
being in a gas-filled room when a gas leak ignites and results in a
combustion explosion.

A sudden change in smoke color from black to white, accompanied by a
strong smell and taste of fuel oil, is a warning sign of the white ghost.
Monitoring the color of the smoke escaping from the chimney or building
openings on your arrival and noting its change from black or gray to
pearly white may give you an advanced warning of the white ghost and alert
you to the possibility of an explosion. If smoke suddenly stops coming out
of the chimney, suspect a reversal of draft or a damaged flue. The smoke
is now exiting somewhere other than from the chimney and can be filling up
the basement. If this smoke contains large amounts of vaporized oil, you
may be moments away from a devastating white ghost explosion.

Treat the white ghost like a gas leak. Enter the vapor cloud only if
absolutely necessary and under the protection of a handline. If you are in
the building when the smoke turns white, open your handline for protection
and back out. If possible, shut the fuel and electric supply to the burner
and stay away from cellar or basement openings. Remember, after the vapor
ignites, flames may blow out from these openings. If the building is
occupied, consider evacuation, and stretch handlines for protection. If
you opt for an interior attack, stretch and have ready a backup line to
assist the initial line. Consider the potential for fire spread up though
openings in the first floor and via interior stairways as well as from
autoexposure to the lower floors via the cellar or basement exterior
openings. Stretching interior handlines into the building when a white
ghost explosion is imminent will put firefighters in danger of being
engulfed in flames and of structural collapse. Only consider this if life
is in danger in the building. Instead, be ready to stretch lines to the
basement and first floor to control any resultant fire, after you have
verified structural stability.

Ventilate the building without exposing yourself to possible injury
from the flame that may vent from the basement windows. You can use a fog
line from the exterior to help vent the area and to saturate the vapor
cloud with water, making it harder to ignite. If you can do so safely,
shut the fuel and electrical supply to the burner. Remember, however, that
any spark created by throwing the burner's safety switch may provide an
ignition source to trigger the white ghost.

GENERAL TACTICS

If present, shut off the emergency electrical shutoff to the burner. It
is typically found at the top of cellar stairs in private dwellings and is
indicated by a red switch plate labeled "Oil Burner Emergency Shutoff
Switch" or similar wording. In a commercial building or multiple
dwelling, this shutoff may be found outside of the burner room or just
inside the door. This, however, is not always a sure method of shutting
the electrical supply. The switch may be defective or may not even be
connected to the burner's electrical system. The switch may even be
mounted upside down, so that flipping the lever up would actually shut the
burner down and flipping it down would turn the burner on.

At all oil burner emergencies, one of your first actions should be to
shut off the fuel supply to the burner. This will prevent any additional
fuel from being added to an existing fire. Two fuel shutoffs may exist,
one at the tank and another at the burner. You must shut both as a
precaution if safety permits, because one may not function properly and
may continue to allow fuel to flow to the burner. If the shutoffs do not
stop the flow of fuel, you may be able to crimp the copper piping
supplying fuel oil to the burner, but take care not to rupture the pipe.

Generally, it is a good idea to stay away from the front of an oil
burner when operating at oil burner emergencies or fires. This is where
you will find the door to the firebox and the peephole, and it can be a
dangerous place should the door be blown off or a jet of flame leap out of
the firebox. When it is necessary to operate in the front of the burner,
stay low, beneath the firebox door and to the side if possible. This
should place you out of the way of the door and any flame that is blown
out of the burner.

Be alert to the possibility that the oil burner might use natural gas
rather than electricity to ignite the oil. This is the case in some larger
burners in commercial occupancies as well as in large apartment houses. An
oil fire in such a burner might damage the gas line, resulting in a gas
leak. Shut down the oil feed and the gas supply.

When you are called to an oil burner-related incident, you are expected
to mitigate the hazard, not repair the problem. Repairing the problem
leaves you and your department exposed to legal action should the burner
malfunction after your repair, so limit yourself to removing the danger.

Issue an order to have the burner serviced by a licensed oil burner
repair service. If the occupant turns the burner back on after you leave
the scene, it is likely that the problem will recur or worsen. You will be
called back to the scene, and this time it might prove dangerous to the
occupant or to firefighters. You must make sure that the occupant
understands that the burner is not safe to turn back on.

There are many possible causes of oil burner emergencies and fires.
Fortunately, despite human error and poor maintenance practices, the
millions of oil burners in use today function without a mishap year after
year. When they do malfunction, the fire department is called and usually
remedies the situation with little effort. But never forget that these
seemingly harmless emergencies can and sometimes do turn deadly, whether
it be from fire, explosion, or carbon monoxide poisoning, and you must be
ever on guard against such instances.

FRANK C. MONTAGNA, a 30-year veteran of the fire service, is a
battalion chief with the Fire Department of New York. He has been an
instructor at the FDNY Probationary Firefighters School, the officer in
command of the FDNY Chauffeur Training School, and an adjunct lecturer at
John Jay College in New York City. He is a member of the FDNY Chief's
Association and is the author of Responding to Routine Emergencies (Fire
Engineering, 1999). Montagna has a bachelor's degree in fire science and
lectures on firefighting-related topics.

Fuel Oil Explosions

By Vincent Dunn-Fuel oil explosions kill and injure firefighters
in several ways. The blast can blow personnel across a street; flying
glass and shrapnel can decapitate; flame accompanying the explosion can
cause serious burns; and an explosion can collapse walls, partitions, and
iron shutters, crushing firefighters beneath them. A fuel oil explosion is
one type of blast that occurs at fires. Fuel oil comes in several grades,
number 1 to 5 grade oil, and has the following general fire hazard
properties: a flashpoint of 1007F to 1507F, a flammable (explosive) range
of 0.7 to 5 percent when mixed with air, and an ignition temperature of
4947F.

DEFINITIONS

Fire protection engineers classify explosions into three broad
categories: physical explosion, physical/chemical reaction, and chemical
reaction. A fuel oil explosion would be classified as a chemical
reaction-type blast called a combustion explosion. The same chemical
reaction and explosive ingredients are present in a fuel oil explosion as
are in any ordinary combustion explosion: fuel, oxygen, and heat. The fuel
in a combustion engine explosion driving an automobile is gasoline; the
fuel in a fuel oil explosion is diesel oil vapors.

Fire protection engineers define the term explosion as an
"effect" produced by a sudden violent expansion of gases. One of
the "effects" of an explosion is shock waves, which shatter
windows; blow down firefighters; and collapse walls.

There are two important facts to know about any other type of
explosion. One is that an explosion can occur even though the gas or vapor
does not fill the entire room. If the explosive mixture concentration of
fuel oil, air, and heat are in one corner of a large, smoke-filled cellar,
the entire area could explode when firefighters enter to search and allow
fresh air to enter with them. The other fact is that it does not take much
explosive pressure in a confined space for an explosion to cause
destruction and death. (For more information on explosion pressures, see
the NFPA Fire Protection Handbook, 18th Edition, Section 1/Chapter 6, page
1-69.)

PREVENTING DEATH AND INJURY

Fortunately, firefighting experience shows us most explosions occurring
at fires such as flammable liquid and fuel oil explosions are low-pressure
blasts and create peak pressures less than 7 to 8 psi. Glass shatters,
firefighters are knocked down, and partition walls collapse.

We must determine ways to manage and control the risk of explosions at
fuel oil firefighting operations. We must develop ways to reduce chances
of death and injury from such an explosion. There are firefighting tactics
that can reduce the destructive effects of a fuel oil explosion. The
recognized tactics include venting, quenching, and flanking.

Venting. Opening doors and windows to the cellar areas is one of the
most effective methods of protecting firefighters from a fuel oil
explosion. Even if the explosion occurs, the blast may be diverted out of
the vent opening away from the firefighters advancing the hoseline.

Quenching. Quenching the superheated confined fire area is another
safety and survival tactic firefighters can use to prevent fuel oil
explosions. Before entering a room that exhibits signs of an explosive
atmosphere, position a charged hoseline near the entrance. Firefighters in
full protective equipment should immediately discharge a hose stream into
a fire area when it is opened up. This water can cool a potentially
explosive atmosphere. This action-taken before the searching firefighters
and entrained air enter a burning, confined, potentially explosive fire
area-might break up the explosive mixture. This is not as effective as
roof venting, but sometimes it is the only alternative.

Flanking. When there can be no venting or quenching, firefighters can
protect themselves from a fuel oil explosion by flanking a doorway with
hoselines. The officer in command can order one or two hoselines into
position-each one positioned at the side of a door leading to the room
that is suspected of exploding. After the hoselines are charged with water
and firefighters are in full protective equipment, the door and windows
are vented. Firefighters are then safely out of the path of any potential
explosive blast coming out of the opening. Water can be directed into the
potentially explosive area.

LESSONS LEARNED

We must teach the warning signs of fuel oil explosions to rookie
firefighters. The signs are reversal of air pulling smoke back into a
smoke-filled doorway, black smoke pushing out around a closed door or
window frames, and glass windows stained with smoke condensation and
pulsating from the pressure of a fire. These warning signs are important
to know but, even more important, firefighters must know that explosions
happen fast, sometimes even too fast for them to take cover and protect
themselves. The only real protection from the blast of exploding fuel oil
or any explosion is full protective gear: helmets, hoods, gloves, boots,
bunker pants, coat, and face mask. Protective fire gear may be hot, may be
cumbersome, and may slow you down; however, the equipment that
firefighters caught in an explosion have will determine whether they
survive the blast and how serious the burns will be.